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Spalding Labs Fly Parasitic Wasps

By Spalding Labs

Last reviewed: December 2025

Fly Predators are beneficial parasitic wasps that destroy fly pupae before they emerge, providing natural biological control without chemicals.

Overview

Fly Predators (also called fly parasites or parasitic wasps) are tiny beneficial insects that attack and kill pest fly pupae in the manure before adult flies emerge. They provide chemical-free fly control.

How They Work

Biological Control

Female parasitic wasps:

  • Search for fly pupae in manure
  • Deposit eggs inside the pupal case
  • Wasp larvae consume fly pupae
  • Adult wasps emerge instead of adult flies
  • Target Species

    Effective against:

  • House flies
  • Stable flies
  • Biting flies
  • Application Program

    Regular Releases

    Fly Predators are released:

  • Every 2-4 weeks during fly season
  • In areas of manure accumulation
  • Near animal housing
  • Around feed areas
  • Quantity

    Number needed based on:

  • Animal count
  • Fly pressure
  • Farm conditions
  • Advantages

    No Chemicals

    Completely natural control method with:

  • No resistance development
  • No residue concerns
  • Safe for animals and humans
  • Environmentally sustainable
  • Complementary Strategy

    Works alongside other control methods without interference.

    Best Results Tips

    Timing

    Begin releases before fly season starts (early spring).

    Placement

    Release near manure accumulation areas, not in clean areas.

    Consistency

    Maintain regular releases throughout the season.

    Sanitation

    Reduce breeding sites through good manure management.

    Species Selection

    Spalding Labs provides mixed species matched to regional conditions and target flies.

    Key Features

    • Biological Control: Natural fly control using beneficial insects, not chemicals
    • Targeted Delivery: Regular shipments throughout fly season customized to your needs
    • Self-Dispersing: Wasps actively seek out fly pupae across your facility
    • Cumulative Effect: Populations build over the season for increasing control
    • No Resistance: Biological control mechanisms avoid resistance development
    • Organic Compatible: Acceptable for organic dairy operations

    Ideal For

    Farm Types: Organic dairy farms, Pasture-based operations, Small to medium dairies, Farms near residential areas

    Pricing Information

    Here is the pricing information for Fly Parasitic Wasps:

    Biological fly control using parasitic wasps released throughout fly season.

    Pricing Model: Monthly release subscription program

    Spalding Labs: 1-888-880-1579. Ships direct to farm on customized schedule.

    Pros & Considerations

    Advantages:
    • Chemical-free fly control method
    • Compatible with organic certification
    • No resistance development possible
    • Safe for animals, workers, and environment
    • Cumulative effect builds throughout season
    • Customized programs for your operation
    Considerations:
    • Requires commitment to full-season program
    • Cannot eliminate 100% of flies alone
    • Less effective if neighbors have untreated fly sources
    • Takes time to establish effective populations
    • Requires proper release protocols for best results

    Evaluation Questions

    Key questions to consider when evaluating Fly Parasitic Wasps:

    1. Are you pursuing organic certification?
    2. What is your current fly control program?
    3. How severe is your typical fly pressure?
    4. Are there neighboring fly sources you cannot control?
    5. Are you willing to commit to season-long releases?
    6. What is your budget for biological control products?
    7. Do you have concerns about chemical pesticide use?
    8. How will you distribute the parasites when they arrive?

    Explore Pest & Fly Control

    Explore all Pest & Fly Control solutions in the Therio Dairy Directory to compare features, pricing, and alternatives.

    Browse All Pest & Fly Control Solutions →

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